A report in the recent literature has described the selective dopamine D-1 receptor binding properties of R-(+)-8-chloro-2,3,4,5-tetrahydro-3-methyl-5-phenyl-1H-3-benzazepin-7-ol [J. Pharmacol. Exp. Ther., 226, 462 (1983)]. This selectivity is reported to be 2500 fold or virtually to the exclusion of the dopamine D-2 receptors. Such specificity indicates that the compound may possess novel antipsychotic effects and low liability for producing side effects such as extrapyramidal effects in humans. This is so because D-1 receptor antagonism like D-2 receptor antagonism is associated with antipsychotic effects in laboratory animal models but D-2 receptor antagonism is also associated with the untoward side-effects characteristic of most known neuroleptics (e.g., hyperprolactinemia in animals and humans).
The compound's high specificity for the dopamine D-1 receptor is a novel feature and is unlike standard neuroleptics. This novel feature makes the compound ideally suited for identifying other candidates for their potential as antipsychotic drugs.